Pump



Jan. 4, 1955 F. M. EVANS 2,693,530

PUMP

Filed Jan. 25, 1951 2 Sheets-Sheet l Fig.7 Fig-5 izw mar FJEZEvma Jan.4, 1955 F. M. EVANS 2,698,530

PUMP

Filed Jan. 25, 1951 2 Sheets-Sheet 2 United States Patent PUMP FraserMackie Evans, Acton, London, England, assignor to C. A. V. Limited,Acton, London, England Application January 23, 1951, Serial No. 207,254

Claims priority, application Great Britain January 26, 1950 3 Claims.(Cl. 103-44) This invention relates to pumps, and particularly pumps forsupplying petrol or like liquid Iuel to engines under high pressure, thepumps being of the kind in which measured quantities of the liquid aredischarged from a measuring chamber by a freely movable (or shuttle)piston under the action of fluid pressure.

When the liquid dealt with by such a pump is of the kind used, forexample, as a fuel for a diesel or compression ignition engine, that isto say a so-called heavy fuel, no dlrficulty is experienced indischarging the liquid to the engine at high pressure. But when theliquid is petrol or other like light and highly mobile fuel, ashuttletype pump of conventional construction is found to beunsatisfactory when the pressure at which delivery is required is of theorder of, for example, 100 lbs/sq. inch., this being attributable atleast in part to unavoidable internal leakages.

The object of the present invention is to enable a pump of the kindabove specified to be successfully employed for supplying light liquidfuels or highly mobile liquids under considerable pressure, and theinvention comprises a pump of the said kind adapted for the actuation ofthe shuttle-piston or pistons by liquid other, and of a greaterviscosity, than the liquid to be delivered.

in the accompanying drawings:

Figure l is a sectional side elevation of a pump em bodying theinvention.

Figures 2a, 2b, 2c and 2d are cross sections taken respectively on thelines A-A, BB, 0-0 and D-D of Figure 1.

Figures 3a, 3b, 3c and 3d are respectively similar views to Figures 2ato 2d showing the rotatable part in a different position.

Figure 4 is a sectional side elevation of another pump embodying theinvention.

Figures 5 and 6 are cross sections on the lines 55 and 6-6 (Figure 4)respectively.

Figure 7 is a fragmentary sectional plan on the line 77 (Figure 4).

Referring to Figures 1-3, there is provided in a bore in a body part a,a rotary cylindrical distributing valve b having a pair of coaxial boresc, d, one of them containing a shuttle-piston e, and the other ashuttle-piston f, a thrust piece g situated between and in contact withthe pistons being slidable through a partition separating the adjacentends of the bores.

In the body part a are provided two sets of passages, one set beingindicated by h to it and the other set by i to i The passages h to itserve, in conjunction with radial ports 10 to 10 and 11 to 11 in thepiston valve b, to conduct the piston-actuating liquid (which may beengine lubricating oil) to and from the chambers 12, 13 formed by theparts of the bores c, d at the remote ends of the pistons e, 1. Anyconvenient pump may be used for supplying the piston-actuating liquidfrom a sump k to the passages h h and k and for returning this liquidfrom the passages h k and h to the sump. For this purpose the passages hk and 11 are interconnected in any convenient manner, and the passages hI2 and h are likewise interconnected, the interconnections beingindicated diagrammatically by dotted lines in Figures 2a, 2d, 3a and 3d.The other passages i to i serve, in conjunction with additional radialports 14, 15 in the piston valve b, to conduct petrol or other lightliquid fuel to and from the chambers 16, 17 formed by the parts of thebores c, d at the adjacent ends of the pistons e, f. The light liquidfuel is supplied from 2,698,580 iatented Jan. 4, 1955 any convenientsource (not shown) to the passage i which is connected to the passages 1and i in any convenient manner as indicated diagrammatically by dottedlines in Figures 2b, 20, 3b and 3c. 'lne passages i, i i i 1' and i areintended to be connected to engine cylinders (not shown) required to besupplied With liquid fuel.

Starting with the various parts of the pump occupying the positionsshown in Figures l, 2a, 2b, 2c and 2d, it will be seen thatpistonactuating liquid enters the chamber 12 via the passages h h and I1and ports 10, 10 and 10 The accompanying movement or the piston e(towards the right in Figure 1) causes liquid fuel to be discharged fromthe chamber 16 via the port 15 and the passage i 'lhis movement of thepiston e is transmitted by the thrust piece 3 to the other piston f, andliquid fuel enters the chamber 17 via the passage 1' and the port 14.Meanwhile piston-actuating liquid escapes from the chamber 13, via theports 11 11 and 11 and passages h h and h On rotation of the valve 12 toits next position as shown in Figures 3a to 3a, piston-actuating liquidis supplied to chamber 13, via passages h h and h and ports 10 10 and 10The accompanying movement of the piston 1 (towards the left in Figure 1)causes liquid fuel to be discharged from the chamber 17 via port 14 andpassage i This movement of the piston f is transmitted by the thrustpiece g to the other piston e, and liquid fuel enters the chamber 16 viapassage i and port 15. Meanwhile piston-actuating liquid escapes fromthe chamber 12 via ports 10 10 and 10 and passages W, h and I2 Continuedrotation of the valve is accompanied by joint reciprocatory movements ofthe pistons. The extent of movement of the pistons, and hence thequantity of petrol discharged in each stroke is determined by stops m, nin the outer ends of the bores, one of which (n) is adjustable.

By the use of ordinary engine lubricating oil, or other liquid having asuitably higher viscosity than the petrol, both pistons are effectivelysealed against leakage of the petrol past the pistons and consequentlythe petrol can be discharged at high pressures. Further, the shuttlepumpcan be supplied with fuel-liquid from a low pressure source.

Referring to Figures 4-7 there is provided in a body part a a gear pumpcomprising at least one pair of interengaging gear wheels 0. Each gearwheel has extending coaxially from one of its sides a hollow spindle pwhich forms the rotary barrel of a shuttle-type pump, and which isrotatably supported in a bore in the body part a. In the bore of thebarrel is contained an axially slidable shuttle piston q loaded by aspring r. Also in each barrel is formed a radial port 20 whichcooperates with inlet passages 21 and outlet passages 22 in the bodypart.

The face of each gear Wheel at the side remote from the associatedbarrel is recessed to form ports .9 which co-operate with ports passages24 in the contiguous face of the body part, whereby the liquid impelledby the gear pump can be admitted to and released from the adjacent endof the associated shuttle. This liquid is admitted to the pump body partat r from a sump (not shown) and returned to the sump at u by way of aspring-loaded relief valve (not shown). The length of travel of eachshuttle piston is controlled in part by a stop v in the associatedbarrel, and in part by an adjustable stop w in the body part, actingrespectively on the opposite ends of the shuttle. The stops w areadjustable by a lever x pivotally mounted on the body part.

Motion is imparted to the gear pump by a driving spindle y connected toone of the barrels 11.

When the pump is in action the liquid associated with the gear pump,which may be oil of considerably higher viscosity than the fuel or otherlight and mobile liquid to be delivered, and which is used as a motiveliquid for moving the pistons q in one direction, is alternatelyadmitted to and released from corresponding ends of thepiston-containing bores under the control of the ports 2 and passages24, the admission of such liquid to either of these bore ends beingaccompanied by release of liquid from the other, so that while eitherpiston q is being moved by the motive liquid against the action of itsloading spring r, the other is being moved in the opposite direction byits loading spring. Movement of each piston q by the motive liquidcauses fuel or other light and mobile liquid to be discharged from thecorresponding pump barrel p via the associated port and the outletpassage 22 communicating therewith, whilst return movement of the pistonby its spring loading causes the pump barrel to be recharged with fuelor other light and mobile liquid via the corresponding port 20 and theinlet passage 21 communicating therewith, the rotational movements ofthe barrels serving to bring the ports 20 into communication alternatelywith the associated inlet and outlet passages.

The invention is not, however, restricted to the examples abovedescribed, as the same underlying idea may be embodied in a variety offorms of pumps for dealing with light fuels or other liquids.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:

l. A liquid pump comprising in combination a stationary body having abore therein, a rotary member mounted in said bore and having a secondbore therein, a shuttle-piston slidably mounted in said second bore,passages and ports provided respectively in said body and member andarranged to co-operate with each other for permitting light and mobileliquid to be supplied to and subsequently discharged from said secondbore at one side of said shuttle-piston, and additional passages andports provided respectively in said body and member and arranged toco-operate with each other to permit a motive liquid of greaterviscosity than the light and mobile liquid to flow into and out of saidsecond bore at the other side of said shuttle-piston, the latter beingmovable by the motive liquid in the direction for discharging the lightand mobile liquid previously supplied to said second bore, and meansbeing-arranged to act on said shuttle-piston formoving the latter in theop-- posite direction to permit recharging of said second bore withlight and mobile liquid preparatory to the next movement of saidshuttle-piston by the motive liquid.

2. A liquid pump comprising in combination a stationary body having abore therein, a rotary cylindrical valve mounted in the bore of saidbody and having a pair of coaxial bores therein, a partition separatingadjacent ends of said coaxial bores, a pair of shuttle-pistons slidablymounted respectively in said coaxial bores, passages and ports providedrespectively in said body and valve and arranged to co-operate with eachother for permitting light and mobile liquid to be supplied to andsubsequently discharged from said coaxial bores at the sides of saidpistons adjacent to each other, additional passages and ports alsoprovided respectively in said body and valve and arranged to co-operatewith each other to permit a motive liquid of greater viscosity than thelight and mobile liquid to flow into and out of said coaxial bores atthe remote sides of said pistons, and a movable thrust piece arrangedbetween said pistons so that movement of either piston by the actionthereon of the motive liquid is transmitted to the other piston by saidthrust piece, each of said pistons being movable by the action thereonof the motive liquid in the direction for discharging light and mobileliquid previously supplied to the corresponding valve bore, and by theaction thereon of said thrust piece in the opposite direction forpermitting recharging of the corresponding valve bore with light andmobile liquid.

3. A liquid pump comprising in combination a stationary body having apair of parallel bores therein, a pair of rotary cylindrical membersrespectively mounted in the bores of said body and each having a boretherein, a pair of interengaging gear wheels provided respectively onadjacent ends of said members and forming with said body a gear pump, apair of shuttle-pistons slidably mounted respectively in the bores ofsaid members, springs acting on said pistons, passages and portsprovided respectively in said members and body and arranged toco-operate with each other for permitting light and mobile liquid to besupplied to and discharged from the bores of said members at the sidesof said pistons remote from said pump, additional passages and portsprovided respectively in said body and gear wheels and arranged toco-operate with each other to permit a motive liquid of greaterviscosity than the light and mobile liquid to be supplied by the pump toand discharged from the bores of said members at the other sides of saidpistons, the latter being movable by the action of the motive fluidthereon in one direction for discharging light and mobile liquidpreviously supplied to the bores of said members, and by said springs inthe opposite direction for permitting recharging of the last mentionedbores with light and mobile liquid.

References Cited in the file of this patent UNITED STATES PATENTS2,336,446 Tucker et a1. Dec. 7, 1943 2,484,884 Hanna Oct. 18, 19492,592,940 Monoyer Apr. 15, 1952

